Patent GB-1003281-A (GB)
Title: Improvements in or relating to fuel control systems
Inventor: HAROLD RICHARD SCIBBE GEORGE V
IPC: F02M69/46
Filed: 1961-08-29
Abstract: 1,003,281. Regulating I.C. engines. THOMPSON RAMO WOOLDRIDGE Inc. Aug. 29, 1961, No. 31094/61. Heading F1B. In an I.C. engine fuel control system in which variations in ambient air pressure are operable to alter the mechanical advantage of a linkage system having a movement-transmitting member 26, Fig. 1, connected to a variable-displacement fuel pump 21 so as to increase fuel delivery with increased air density and to decrease fuel, delivery with decreased air density, a regulator control device 32, Fig. 10, applies a non-linear displacement force to the linkage system which is a function of pressure in the engine intake manifold. The output of engine-driven positive displacement fuel pump 21, which supplies injectors 14 through a distributer 17, is controlled by rotation of a crank arm 24 connected to a pivotal link 27 by rod 26. A vacuum motor 32 which moves rod 29 in response to inlet manifold pressure has a diaphragm 99, dividing the vacuum motor into a chamber 103 which is exposed to atmosphere and a chamber 104 subjected to the inlet manifold pressure through conduit 33. The non-linear fuel metering/intake manifold pressure relationship is provided by biasing diaphragm 99 with a power range spring 107, a cruising range spring 108 and an idling range spring 122. The connection point between the rod 26 and link 27 is varied in dependence on atmospheric pressure by replacing link 27 with a link 81, Fig. 5, carrying a pressure capsule 83 which moves rod 84 to pivot arm 86 thus moving the end 92 of rod 26 along a diagonal slot 91. For cold running, link 27 is moved by a spiral bi-metallic thermosensitive element which the end 53, Fig. 2, of which acts through arm 56, shaft 57, arm 44, rod 43 and bell-crank 41 to move rod 34 attached to the end of link 27. In order to cut out starting compensation, arm 56 is connected to a piston 73, loosely fitted in chamber 76 through which gas flows from passage 47. A flow of exhaust-heated air passes over the bi-metallic element and out past the piston 73 through a port 77 leading to the intake manifold. When the vacuum load on the piston 73 increases as soon as the engine is started the arm 56 is moved counter-clockwise to reduce the starting compensation and as the compensator and bimetallic element are warmed up the linkage is permitted to move towards the hot position. To increase the setting of throttle 13 at starting an extension 61 on bell-crank arm 59 rotates a freely-mounted arm 62 counter clockwise which rotates a fast idle cam 64 clockwise, thus bringing a series of stepped abutments 67 into alignment with an adjustable stop screw 68 mounted on an arm 69 which is connected through shaft 37 with throttle 13. When the engine is warm and screw 68 is not in engagement with cam 64, the latter is rotated by gravity into the normal operating position. Starting compensation can be cut out manually by moving the throttle so that extension 71 engages projection 72 to pivot cam 64 counter clockwise thus pivoting bell-crank 41 and link 56 to draw rod 34 to the left in Fig. 2. In modifications to the vacuum motor 32 a single variable rate spring may be used in place of the three springs or the adjustable idling spring or the adjustment screw 123 may be omitted.